Stegoelmis figueiredoensis, Fernandes, André S., Passos, Maria Inês S. & Hamada, Neusa, 2011

Fernandes, André S., Passos, Maria Inês S. & Hamada, Neusa, 2011, Stegoelmis Hinton, 1939 (Coleoptera: Elmidae: Elminae) in Brazil: two new species and a key to the Brazilian species, Zootaxa 2921, pp. 56-64 : 58-61

Stegoelmis figueiredoensis sp. nov.

( Figs. 3–7 )

Diagnosis. Elytral apices rounded and not dehiscent; metatibial cleaning fringe of tomentum indistinct; hypomeron with punctures much coarser than those on pronotal disc; ventrite I with coarse punctures only across apical 2/3; parameres and median lobe long and slender, apex rounded.

Description. Holotype: male ( Figs. 3–6 ). Length 4.2 mm, greatest width 1.88 mm. Body ( Figs. 3, 4 ) robust, subparallel; body sparsely covered with fine, short, recumbent and pale setae; dorsal surface covered with punctures equal to the diameter of eye facets and spaced by two times their diameter; scutellum glabrous; ventral surface covered with punctures one to four times the diameter of eye facets, coarser on sides of prosternum, mesoventrite, sides of metaventrite, hypomeron, sides and anterior 2/3 of ventrite I; dorsum and venter covered with plastron.

Head ( Figs. 3, 4 ): Short and deep longitudinal impression between bases of antennae. Eyes protuberant, laterally rounded, separated by a distance of 0.4 mm. Antenna with 11 segments, long and slender, first and last segments slightly swollen and twice as long as the remaining segments. Frontclypeal suture present between bases of antennae. Clypeus rectangular, as long as and 1.5 times wider than labrum; anterior margin concave; lateral angles rounded. Labrum rectangular; anterior margin slightly convex; anterolateral angles rounded; row of moderately long pale setae on middle; row of short pale setae on anterior margin. Maxillary palpus with four segments; last segment swollen, as long as second and third segments combined. Labial palpus with three segments; last segment swollen, as long as the remaining segments combined. Gula narrower than submentum.

Color ( Figs. 3, 4 ): Areas covered with plastron: cuticle grayish-brown and opaque, except legs (reddishbrown). Areas not covered with plastron: cuticle reddish-brown and shiny, except eyes (black).

Thorax ( Figs. 3, 4 ): Pronotum ( Fig. 3 ) wider at base (1.36 mm) than long (1.1 mm); without carinae; impressions on disc (one deep longitudinal, median, from posterior to anterior margin); four gibbosities (two median, one on each side, on basal 2/5; two lateral, on each side, on basal 4/9); anterolateral angles rounded; concave at middle, extending over base of head; lateral margin feebly sinuate, smooth; posterior angles produced, acute; posterior margin with three arches, two broad, one on each side in front of elytron, and one narrow in front of scutellum. Elytra ( Fig. 3 ) subparallel; longer (2.88 mm) than wide, (maximum width, at apical 1/3, 1.87 mm); humeral angle broadly rounded, tumid; without carinae; posterolateral angles with distinct acute protuberance, lateral margins smooth; apices rounded, not dehiscent; deep striae and punctures; disc with punctures separated by two to four times their diameters, half as wide as intervals between striae. Scutellum ( Fig. 3 ) flat; subtriangular; longer than wide; wider at base; anterior margin convex; posterior angle acute. Prosternum ( Fig. 4 ) with anterior margin sinuate, concave at middle; anterolateral angles rounded; without impressions or carinae. Prosternal process longer (0.41 mm) than wide at middle (0.19 mm); extending beyond anterior coxae; narrowed to apex; lateral margin broadly concave, apex truncate. Mesoventrite ( Fig. 4 ) shorter (0.40 mm) than wide between coxae (0.51 mm); shorter than prosternum; anterior margin concave; posterior margin between mesocoxae convex. Metaventrite ( Fig. 4 ) with median, longitudinal impression extending until apical 2/7; anterior margin between mesocoxae concave; posterior margin between metacoxae convex; posterior portion in front of metacoxae with transverse arched impression. Legs ( Figs. 3, 4 ) long, robust; pro- and mesocoxae globular; protibiae with two (anterior and internal margins) short fringes of tomentum on apices; meso- and metatibiae with one (internal margin) short fringe of tomentum on apices; last tarsal segment longer than remaining segments combined; tarsal claws without basal teeth.

Abdomen ( Fig. 4 ): Longer (1.83 mm) than wide (maximum width, ventrite I, 1.68 mm). Ventrite I ( Fig. 4 ) with anterior margin between metacoxae sinuate; without carinae or impressions; disc depressed on anterior 1/2. Ventrite III ( Fig. 3 ) with rounded posterolateral projection. Ventrite V ( Fig. 4 ) without posterolateral toothlike projection; posterior margin convex, with short setae.

Male Genitalia ( Figs. 5, 6 ): Paramere ( Figs. 5, 6 ) long, as long as median lobe; in dorsal view ( Fig. 4 ) elongate; external lateral margin broadly and feebly concave; internal lateral margin broadly and feebly convex; base oblique and truncate, with external angles produced; apical 1/15 moderately curved to median lobe; apex rounded; in lateral view ( Fig. 6 ) curved to venter; gradually narrowed to apex; basal falciform projection on ventral margin; apex rounded with very short setae. Median lobe ( Figs. 5, 6 ) long, more than tree times the length of basal lobe; in dorsal view ( Fig. 5 ), lateral margin straight; apex rounded; in lateral view ( Fig. 6 ) curved to venter; apical portion expanded ventrally; apex rounded.

Plastron: Completely covering dorsal and ventral surface, except: antennae; eyes; clipeo; labrum; middle of metaventrite; apex of tibiae; tarsus.

Female. Externally similar to male.

Female Genitalia ( Fig. 7 ): Coxites with 2/5 the length of the styli; in dorsal view: about as long as wide. Styli elongate; in dorsal view: basal segment narrowed from base until basal 3/5; apex of each basal segment truncate, with two minute stout setae on the apical surface; apical segment narrow, subclavate and with 1/9 the length of the basal segment.

Intraspecific variation. Size (n = 8): length 3.90 – 4.44 mm, maximun width 1.80 – 1.91 mm. Color: small variation on tonality. Morphology: shape of prosternal process apices vary from truncate to feebly sinuate.

Type locality. Sossego da Pantera, Igarapé da Onça Stream, Km 20, Amazonas State Highway 240 (AM-240), Presidente Figueiredo Municipality, Amazonas State, Brazil (2º0’52”S, 60º6’43”W).

Type series. Holotype (Male): BRAZIL: Amazonas: Presidente Figueiredo, Km 20, AM-240, Sossego da Pantera, Igarapé da Onça Sream, 2º0’52”S, 60º6’43”W, Pensylvania light trap, with white light. A. M. O. Pes leg. 3 – 5/viii/2000 ( INPA). Paratypes: 2 females, same data as holotype ( INPA); 1 male, same data as holotype ( NMNH); 1 male, same data as holotype except ‘Km 13, AM-240, Sr. Clovis Propriety, 2º02’02’’S, 59º51’47’’W, D-Net, A. S. Fernandes leg. 22/x/2008 ’ ( DZRJ); 1 female, same data as holotype except ‘Km 13, AM-240, Sr. Clovis Propriety 2º02’02’’S, 59º51’47’’W, D-Net, A. S. Fernandes leg. 22/x/2008 ’ ( NMNH); 1 female, same data as holotype except ‘Km 13, AM-240, Sr. Clovis Propriety 2º02’02’’S, 59º51’47’’W, D-Net, A. S. Fernandes leg. 22/x/2008 ’ ( DZRJ).

Habitat. The specimens were collected with light traps and D-Nets along second-order streams with bedrock streambeds, in fragments of terra firme (upland) forest in northern Brazil. Stegoelmis figueirenis sp. nov. specimens were found in riffles on leaf packs in depths of less than 30 cm in shaded areas.

Etymology. The species epithet ( figueiredoensis ) is a reference to Presidente Figueiredo municipality, where the holotype was found.

Comparative notes. From the known species of Stegoelmis , S. figueiredoensis sp. nov. is closer to S. selva Spangler 1990 , S. tuberosa, Spangler 1990 , S. verrucata and S. fera Spangler, 1990 by having rounded and not dehiscent elytral apices ( Fig. 2 ) ( Spangler, 1990).

Stegoelmis figueiredoensis sp. nov. can be distinguished from S. selva by the presence of a deep transversal impression between bases of antennae (absent in S. selva ) and by the absence of a dense fringe of long golden setae on the apex of ventrite V of males ( Fig. 4 ) (present in S. selva ). Stegoelmis figueiredoensis can be distinguished from S. tuberosa , S. verrucata and S. fera by the presence of coarse punctures occupying the apical 2/3 of ventrite I ( Fig. 4 ) (occupying apical 1/ 3 in S. tuberosa and occupying ventrites I and II in S. verrucata and S. fera ). Stegoelmis figueiredoensis also can be distinguished from S. verrucata by the hypomeron with denser and coarser punctures than those of pronotum (punctures of hypomeron as coarse as those of pronotum in S. verrucata ).

Stegoelmis figueiredoensis sp. nov. can be distinguished from all known species of Stegoelmis by the morphology of the male genitalia ( Figs. 5, 6 ): parameres separated in dorsal view (fused on base in S. tuberosa ); median lobe gradually narrowed to apex and apex rounded in ventral view (abruptly narrowed on apex and apex acute in S. verrucata ); apices of parameres rounded and curved to median lobe (apices acute and straight in S. fera ).

Figures

FIGURES 2 – 4. Stegoelmis shepardi sp. nov.; 2) Dorsal habitus. Stegoelmis figueiredoensis sp. nov.; 3) Dorsal habitus. 4) Ventral habitus. Scale bars: 1.0 mm.

FIGURES 5 – 7. Stegoelmis figueiredoensis sp. nov.; 5) Male genitalia, dorsal view. 6) Male genitalia, lateral view. 7) Female genitalia, ventral view. Scale bars: 0.25 mm.